<?php

/**
 * @package php-font-lib
 * @link    http://php-font-lib.googlecode.com/
 * @author  Fabien M�nager <fabien.menager@gmail.com>
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 * @version $Id: font_table_loca.cls.php 43 2012-02-05 22:26:53Z fabien.menager $
 */

/**
 * `loca` font table.
 * 
 * @package php-font-lib
 */
class Font_Table_loca extends Font_Table {

    protected function _parse() {
        $font = $this->getFont();
        $offset = $font->pos();

        $indexToLocFormat = $font->getData("head", "indexToLocFormat");
        $numGlyphs = $font->getData("maxp", "numGlyphs");

        $font->seek($offset);

        $data = array();

        // 2 bytes
        if ($indexToLocFormat == 0) {
            $d = $font->read(($numGlyphs + 1) * 2);
            $loc = unpack("n*", $d);

            for ($i = 0; $i <= $numGlyphs; $i++) {
                $data[] = $loc[$i + 1] * 2;
            }
        }

        // 4 bytes
        else if ($indexToLocFormat == 1) {
            $d = $font->read(($numGlyphs + 1) * 4);
            $loc = unpack("N*", $d);

            for ($i = 0; $i <= $numGlyphs; $i++) {
                $data[] = $loc[$i + 1];
            }
        }

        $this->data = $data;
    }

    function _encode() {
        $font = $this->getFont();
        $data = $this->data;

        $indexToLocFormat = $font->getData("head", "indexToLocFormat");
        $numGlyphs = $font->getData("maxp", "numGlyphs");
        $length = 0;

        // 2 bytes
        if ($indexToLocFormat == 0) {
            for ($i = 0; $i <= $numGlyphs; $i++) {
                $length += $font->writeUInt16($data[$i] / 2);
            }
        }

        // 4 bytes
        else if ($indexToLocFormat == 1) {
            for ($i = 0; $i <= $numGlyphs; $i++) {
                $length += $font->writeUInt32($data[$i]);
            }
        }

        return $length;
    }

}